diff options
Diffstat (limited to 'swift/proxy/controllers/container.py')
| -rw-r--r-- | swift/proxy/controllers/container.py | 140 |
1 files changed, 99 insertions, 41 deletions
diff --git a/swift/proxy/controllers/container.py b/swift/proxy/controllers/container.py index 4102d652a..fe8480ba3 100644 --- a/swift/proxy/controllers/container.py +++ b/swift/proxy/controllers/container.py @@ -21,7 +21,8 @@ from six.moves.urllib.parse import unquote from swift.common.memcached import MemcacheConnectionError from swift.common.utils import public, private, csv_append, Timestamp, \ - config_true_value, ShardRange, cache_from_env, filter_shard_ranges + config_true_value, ShardRange, cache_from_env, filter_namespaces, \ + NamespaceBoundList from swift.common.constraints import check_metadata, CONTAINER_LISTING_LIMIT from swift.common.http import HTTP_ACCEPTED, is_success from swift.common.request_helpers import get_sys_meta_prefix, get_param, \ @@ -109,25 +110,42 @@ class ContainerController(Controller): req.swift_entity_path, concurrency) return resp - def _make_shard_ranges_response_body(self, req, shard_range_dicts): - # filter shard ranges according to request constraints and return a - # serialised list of shard ranges + def _make_namespaces_response_body(self, req, ns_bound_list): + """ + Filter namespaces according to request constraints and return a + serialised list of namespaces. + + :param req: the request object. + :param ns_bound_list: an instance of + :class:`~swift.common.utils.NamespaceBoundList`. + :return: a serialised list of namespaces. + """ marker = get_param(req, 'marker', '') end_marker = get_param(req, 'end_marker') includes = get_param(req, 'includes') reverse = config_true_value(get_param(req, 'reverse')) if reverse: marker, end_marker = end_marker, marker - shard_ranges = [ - ShardRange.from_dict(shard_range) - for shard_range in shard_range_dicts] - shard_ranges = filter_shard_ranges(shard_ranges, includes, marker, - end_marker) + namespaces = ns_bound_list.get_namespaces() + namespaces = filter_namespaces( + namespaces, includes, marker, end_marker) if reverse: - shard_ranges.reverse() - return json.dumps([dict(sr) for sr in shard_ranges]).encode('ascii') + namespaces.reverse() + return json.dumps([dict(ns) for ns in namespaces]).encode('ascii') def _get_shard_ranges_from_cache(self, req, headers): + """ + Try to fetch shard namespace data from cache and, if successful, return + a response. Also return the cache state. + + The response body will be a list of dicts each of which describes + a Namespace (i.e. includes the keys ``lower``, ``upper`` and ``name``). + + :param req: an instance of ``swob.Request``. + :param headers: Headers to be sent with request. + :return: a tuple comprising (an instance of ``swob.Response``or + ``None`` if no namespaces were found in cache, the cache state). + """ infocache = req.environ.setdefault('swift.infocache', {}) memcache = cache_from_env(req.environ, True) cache_key = get_cache_key(self.account_name, @@ -135,11 +153,10 @@ class ContainerController(Controller): shard='listing') resp_body = None - cached_range_dicts = infocache.get(cache_key) - if cached_range_dicts: + ns_bound_list = infocache.get(cache_key) + if ns_bound_list: cache_state = 'infocache_hit' - resp_body = self._make_shard_ranges_response_body( - req, cached_range_dicts) + resp_body = self._make_namespaces_response_body(req, ns_bound_list) elif memcache: skip_chance = \ self.app.container_listing_shard_ranges_skip_cache @@ -147,12 +164,20 @@ class ContainerController(Controller): cache_state = 'skip' else: try: - cached_range_dicts = memcache.get( + cached_namespaces = memcache.get( cache_key, raise_on_error=True) - if cached_range_dicts: + if cached_namespaces: cache_state = 'hit' - resp_body = self._make_shard_ranges_response_body( - req, cached_range_dicts) + if six.PY2: + # json.loads() in memcache.get will convert json + # 'string' to 'unicode' with python2, here we cast + # 'unicode' back to 'str' + cached_namespaces = [ + [lower.encode('utf-8'), name.encode('utf-8')] + for lower, name in cached_namespaces] + ns_bound_list = NamespaceBoundList(cached_namespaces) + resp_body = self._make_namespaces_response_body( + req, ns_bound_list) else: cache_state = 'miss' except MemcacheConnectionError: @@ -162,9 +187,9 @@ class ContainerController(Controller): resp = None else: # shard ranges can be returned from cache - infocache[cache_key] = tuple(cached_range_dicts) + infocache[cache_key] = ns_bound_list self.logger.debug('Found %d shards in cache for %s', - len(cached_range_dicts), req.path_qs) + len(ns_bound_list.bounds), req.path_qs) headers.update({'x-backend-record-type': 'shard', 'x-backend-cached-results': 'true'}) # mimic GetOrHeadHandler.get_working_response... @@ -180,36 +205,62 @@ class ContainerController(Controller): return resp, cache_state def _store_shard_ranges_in_cache(self, req, resp): - # parse shard ranges returned from backend, store them in infocache and - # memcache, and return a list of dicts - cache_key = get_cache_key(self.account_name, self.container_name, - shard='listing') + """ + Parse shard ranges returned from backend, store them in both infocache + and memcache. + + :param req: the request object. + :param resp: the response object for the shard range listing. + :return: an instance of + :class:`~swift.common.utils.NamespaceBoundList`. + """ + # Note: Any gaps in the response's shard ranges will be 'lost' as a + # result of compacting the list of shard ranges to a + # NamespaceBoundList. That is ok. When the cached NamespaceBoundList is + # transformed back to shard range Namespaces to perform a listing, the + # Namespace before each gap will have expanded to include the gap, + # which means that the backend GET to that shard will have an + # end_marker beyond that shard's upper bound, and equal to the next + # available shard's lower. At worst, some misplaced objects, in the gap + # above the shard's upper, may be included in the shard's response. data = self._parse_listing_response(req, resp) backend_shard_ranges = self._parse_shard_ranges(req, data, resp) if backend_shard_ranges is None: return None - cached_range_dicts = [dict(sr) for sr in backend_shard_ranges] + ns_bound_list = NamespaceBoundList.parse(backend_shard_ranges) if resp.headers.get('x-backend-sharding-state') == 'sharded': # cache in infocache even if no shard ranges returned; this # is unexpected but use that result for this request infocache = req.environ.setdefault('swift.infocache', {}) - infocache[cache_key] = tuple(cached_range_dicts) + cache_key = get_cache_key( + self.account_name, self.container_name, shard='listing') + infocache[cache_key] = ns_bound_list memcache = cache_from_env(req.environ, True) - if memcache and cached_range_dicts: + if memcache and ns_bound_list: # cache in memcache only if shard ranges as expected self.logger.debug('Caching %d shards for %s', - len(cached_range_dicts), req.path_qs) - memcache.set(cache_key, cached_range_dicts, + len(ns_bound_list.bounds), req.path_qs) + memcache.set(cache_key, ns_bound_list.bounds, time=self.app.recheck_listing_shard_ranges) - return cached_range_dicts + return ns_bound_list def _get_shard_ranges_from_backend(self, req): - # Make a backend request for shard ranges. The response is cached and - # then returned as a list of dicts. + """ + Make a backend request for shard ranges and return a response. + + The response body will be a list of dicts each of which describes + a Namespace (i.e. includes the keys ``lower``, ``upper`` and ``name``). + If the response headers indicate that the response body contains a + complete list of shard ranges for a sharded container then the response + body will be transformed to a ``NamespaceBoundsList`` and cached. + + :param req: an instance of ``swob.Request``. + :return: an instance of ``swob.Response``. + """ # Note: We instruct the backend server to ignore name constraints in # request params if returning shard ranges so that the response can - # potentially be cached. Only do this if the container state is + # potentially be cached, but we only cache it if the container state is # 'sharded'. We don't attempt to cache shard ranges for a 'sharding' # container as they may include the container itself as a 'gap filler' # for shard ranges that have not yet cleaved; listings from 'gap @@ -232,10 +283,10 @@ class ContainerController(Controller): if (resp_record_type == 'shard' and sharding_state == 'sharded' and complete_listing): - cached_range_dicts = self._store_shard_ranges_in_cache(req, resp) - if cached_range_dicts: - resp.body = self._make_shard_ranges_response_body( - req, cached_range_dicts) + ns_bound_list = self._store_shard_ranges_in_cache(req, resp) + if ns_bound_list: + resp.body = self._make_namespaces_response_body( + req, ns_bound_list) return resp def _record_shard_listing_cache_metrics( @@ -334,7 +385,6 @@ class ContainerController(Controller): params['states'] = 'listing' req.params = params - memcache = cache_from_env(req.environ, True) if (req.method == 'GET' and get_param(req, 'states') == 'listing' and record_type != 'object'): @@ -346,6 +396,7 @@ class ContainerController(Controller): info = None may_get_listing_shards = False + memcache = cache_from_env(req.environ, True) sr_cache_state = None if (may_get_listing_shards and self.app.recheck_listing_shard_ranges > 0 @@ -424,8 +475,15 @@ class ContainerController(Controller): # 'X-Backend-Storage-Policy-Index'. req.headers[policy_key] = resp.headers[policy_key] shard_listing_history.append((self.account_name, self.container_name)) - shard_ranges = [ShardRange.from_dict(data) - for data in json.loads(resp.body)] + # Note: when the response body has been synthesised from cached data, + # each item in the list only has 'name', 'lower' and 'upper' keys. We + # therefore cannot use ShardRange.from_dict(), and the ShardRange + # instances constructed here will only have 'name', 'lower' and 'upper' + # attributes set. + # Ideally we would construct Namespace objects here, but later we use + # the ShardRange account and container properties to access parsed + # parts of the name. + shard_ranges = [ShardRange(**data) for data in json.loads(resp.body)] self.logger.debug('GET listing from %s shards for: %s', len(shard_ranges), req.path_qs) if not shard_ranges: |